The leaves on my austrees are turning yellow and falling off in June. Why would this happen?
The Gardener’s Answer
Hello, Gladys: Austrees are a hybrid willow. They are a cross between a hankow willow (Salix matsudana) and a white willow (Salix alba). Like all members of this genus they are very fast growers, up to 15 feet in one year, and have extensive root systems that require a lot of moisture. Because these trees are such rapid growers their wood is weaker than a slower growing tree and are damaged easily during wind and ice storms. Unfortunately, these trees are not ideal for the home landscape unless they are needed to control soil erosion. Willows are susceptible to a wide range of insect and disease problems so it is difficult to say for certain why the foliage is turning yellow. It may be chlorosis, which is a lack of chlorophyll and can be caused from a few different possibilities such as lack of nutrients, high pH (alkaline soil), and poor drainage. For a positive diagnosis you can take a sample to your County Cooperative Extension Service.